help with idle problem - please

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Mar 18, 2002 | 09:06 AM

Mike263

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Racer

Joined: Jun 2000

Posts: 428

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From: Friendswood Texas

help with idle problem - please

I just replaced my fuel injectors with FMS 24#'s. The car runs great and has the smoothest idle ever. Here's the problem: on three occasions when I have come to a stop the idle "hunts". It goes up and down, up and down, like the ECM is having trouble finding the idle. If I bump the gas it settles down to a smooth idle. It did this once when I just turned off the AC - the smooth idle started to oscillate. I bumped the gas and it settled down.

Any ideas?

BTW I only have about 20 miles on the new injectors.

Mar 18, 2002 | 11:24 AM

vett4cw

Instructor

Joined: Jan 2001

Posts: 126

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From: Murrieta, CA

Re: help with idle problem - please (Mike263)

IAC maybe ?? Have you de-coked the throttle body recently (including the IAC) ??

Mar 18, 2002 | 01:15 PM

JonM

Melting Slicks

Joined: Nov 2000

Posts: 3,388

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From: X

Re: help with idle problem - please (Mike263)

If its acting up when you also fool with the AC I would think it was the IAC. Remove and clean, follow the manuel because they are delicate. Sounds like your ECM is telling the IAC to close, band there may be some carbon in there not allowing it to seat fully or a bad IAC Also while you are at it, check the TPS.

Mar 18, 2002 | 01:20 PM

Mike263

Thread Starter

Racer

Joined: Jun 2000

Posts: 428

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From: Friendswood Texas

Re: help with idle problem - please (JonM)

Thanks, guys. The IAC is only a year old, but the TPS is original. I'll check out both of them.

Mar 18, 2002 | 02:43 PM

Bluevette85

Drifting

Joined: Nov 2001

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From: Latham NY

Re: help with idle problem - please (Mike263)

Try disconnecting the MAF sensor. If the idle is better you have the reason.

Mar 19, 2002 | 01:52 PM

Mike263

Thread Starter

Racer

Joined: Jun 2000

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From: Friendswood Texas

Re: help with idle problem - please (Mike263)

Just a followup.
I unplugged the connector to the IAC and reconnected it. The car had an oscillating idle (450 rpm - 850 rpm) all the time. I repeated the connect/reconnect and now it works great. Either a dirty connector or loose wire? Definitely IAC related.

Mar 19, 2002 | 02:02 PM

KYVette90

Burning Brakes

Joined: Nov 2000

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From: BowlingGreen KY

Re: help with idle problem - please (Mike263)

Did the 86's come with 24# injectors from the factory? I thought they were 19#. If so that may be your problem.

Mar 19, 2002 | 09:35 PM

Mike263

Thread Starter

Racer

Joined: Jun 2000

Posts: 428

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From: Friendswood Texas

Re: help with idle problem - please (KYVette90)

Quote:

Did the 86's come with 24# injectors from the factory? I thought they were 19#. If so that may be your problem.

WOW have you got a beautiful motor, KYVette90!
86's had 22# injectors from the factory - or so I'm told. Now that I've got the IAC working it runs awesome! Starts instantly, idles smooth as glass, pulls hard all the way up to redline. My computer says my average gas mileage is up from 15.3 to 18.6 (no hwy driving) - I plan to check it on the next few fillups. Yipee!
Got the injectors from Summmit based on many recommendations here on the forum. Popped right in. Getting the runners off was not that easy (darn inside bolts), but putting the injectors in, once that was done, was a breeze. Thanks folks!

[Modified by Mike263, 7:38 PM 3/19/2002]